XTR111: XTR111 Error Flag Output Pin Not working properly

Prashant Chavan6

Part Number: XTR111

Hi TI and All,

I have designed XTR111 ckt. for 4mA to 20mA output. It is working fine. But I am facing issue regarding Error flag Output Pin. I have attached fig. for better understanding of ckt.

Observation: EF pin continuously low in the presence of Output load as well. So voltage at Gate of P MOSFET is 0V. And MOSFET is ON . So LED aslo continuously ON. But I want LED should be OFF when Load is connected at output and ON when load is disconnected.

MOSFET Specification : P-Channel MOSFET -60V Vds 20V Vgs SOT-23,OTR- -55C to +150C

So I hope you have understand my problem, hoping for positive reply ASAP.

Prashant

over 5 years ago

0 Zak Kaye over 5 years ago

TI__Mastermind 23050 points

Hi Prashant,

There are 3 reasons the EF pin would pull low: A wire break, high load resistance, or an output voltage level approaching the compliance limitation. Are you certain that none of these things are happening in your circuit?

Have you measured the voltage at the EF pin or just observed the state through the LED? You may want to try lowering the value of your pullup resistor to 10kOhms.

0 Prashant Chavan6 over 5 years ago in reply to Zak Kaye

Intellectual 320 points

Hi Zak,

Thanks for resolving issue, It is because of weak pull up.

Prashant

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XTR111: XTR111 Error Flag Output Pin Not working properly